In the pic, Kardashian, 31, and Harden, 25 appear to have just wrapped up a joint-workout at Cycle House in Los Angeles - a gym that just so happens to be featured on Hollywood Cycle.
And even though the post may be nothing more than synergy between the Keeping up with The Kardashians star and the cast of E!'s latest reality show, it's very telling that Harden appeared in the snapshot alongside her.
Of course, they could just be friends.
We're thinking, though, that the workout coupled with last weekend's flirtatious Vegas trip spell L-O-V-E pretty clearly.